Snopix

Snopix adds reverse-image search to the WordPress media library. Upload
an image (or drop one onto the dashboard widget) and the plugin returns the
visually most similar attachments you already have indexed, ranked by a
composite score over three fingerprints:

• A 64-bit perceptual hash (pHash) over a DCT of the greyscale thumbnail
• A 48-element RGB colour histogram
• A 32-element Sobel edge-orientation histogram

The same fingerprints power the Duplicates tab, which clusters
near-identical attachments so you can keep one and bulk-delete the rest.

Features

• Reverse-image search via the admin dashboard or a [snopix_search] shortcode for
  the front end.
• Block-editor panel on the core Shortcode block for inserting and editing the
  [snopix_search] widget (variant, title, result cap).
• Duplicate detection with per-group “keep” selection and bulk delete.
• Background bulk indexing via WP-Cron — no PHP timeouts on large libraries.
• REST API at /wp-json/snopix/v1/ with rate limiting on the public search
  endpoint.
• Settings panel: search visibility, rate limit, match and duplicate
  thresholds, indexer batch size, and probe downscale ceiling.
• Setting to keep or drop the index when the plugin is uninstalled.
• Tools panel: reindex everything, clear the index, delete orphan rows,
  flush caches.
• Pre-downscale of large probe images before fingerprinting to keep search
  latency bounded.

Supported MIME types

image/jpeg, `image/png`, `image/gif`, `image/webp`, `image/bmp`.

Where data lives

Snopix creates a single custom table, {prefix}snopix_index, that stores one
row per indexed attachment with its three fingerprints. Uninstalling the
plugin drops the table unless you disable Drop data on uninstall in
settings.

Accuracy notice

Snopix is functional, but search ranking, duplicate detection and the
threshold tuning may be less accurate than expected – you may see occasional
false positives or miss visually-similar images depending on your media
library. Please report anything that looks off.